Crimping mechanism in a nut runner

ABSTRACT

A pneumatically powered nut running tool having a rotatable sleeve carrying crimping jaw elements arranged to define a hexagonal opening into which a nut may be received and run down by the jaws when the sleeve is rotated, and which jaw elements are pivotable in another operation of the tool by means of a centrally moving wedge to crimp the nut. The jaw elements have crimping surfaces designed to allow easy retraction of the jaws out of crimping relation with the nut.

[451 Apr. 15, 1975 United States Patent 1 Amtsberg et a1.

1 1 CRIMPING MECHANISM IN A NUT RUNNER Inventors:

Lester A. Amtsberg, Utica; William P i E i c w L h Wallace, Barneveld, both of Assistant ExaminerGene P. Crosby Chicago Pneumatic Tool Company,

New York, N.Y.

May 9, 1973 Attorney, Agent, or Firm-Stephen J. Rudy [73] Assignee:

ABSTRACT [22] Filed:

App]. No.: 358,821

Related US. Application Data A pneumatically powered nut running tool having a rotatable sleeve carrying crimping jaw elements ar- [62] Division of Ser. No. 121,867, March 8, 1971, Pat.

ranged to define a hexagonal opening into which a nut may be received and run down by the jaws when the sleeve is rotated, and which jaw elements are pivotable in another operation of the tool by means of a 02 0 3 001 .3 21 02 MB 7 G SL Um UH 55 55 458 centrally moving wedge to crimp the nut. The aw ele- Field of Search ments have crimping surfaces designed to allow easy retraction of the jaws out of crimping relation with the nut.

[56] References Cited UNITED STATES PATENTS 3 Claims, 10 Drawing Figures 3,646,837 3/1972 Reynolds 81/10 CRIMPING MECHANISM IN A NUT RUNNER BACKGROUND OF THE INVENTION This application is a division of application Ser. No. 121.867 filed Mar. 8. l97l now US. Pat. No. 3.747.441. dated July 24. I973. for a pneumatic tool having combined nut running and crimping mechanism.

This application is directed to the feature of the crimping jaw elements in a nut running and crimping tool.

In a tool embodying the invention. there is provided a rotatable member carrying a group of pivotable jaw elements which provide two distinctive operational functions. namely, as a mcans to run up a standard hexagonal nut upon a bolt to a predetermined seated condition and subsequently as a means to crimp all sides of the nut into tight engagement with the bolt.

The jaw elements are associated with a wedge which is movable axially of the jaw elements with a camming action against tail ends of the jaw elements so as to force lower jaw face portions angularly in the crimping action to penetrate a nut received between the jaw faces.

A characteristic of each element is a flat planar face at its lower inner end area which defines the jaw. This jaw face serves to contribute to an effective nut contact area to achieve defined nut runup; it also is cooperable in a crimping action angularly with a flat side of the nut so as to compressively displace a triangular volume of metal. This structural arrangement is of decided advantage in that it does not allow the jaw to become locked or bound to the nut in the crimping action; and the jaw may. accordingly. be readily released.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing:

FIG. I is a sectional view of a nut runner embodying the invention;

FIG. 2 is a section on line 22 of FIG. 1;

FIG. 3 is a section on line 3-3 of FIG. 1;

FIG. 4 is a section on line 4-4 of FIG. 1;

FIG. 5 is a detail view of the travel wedge;

FIG. 6 is a bottom end view of FIG. 5;

FIG. 7 is a detail showing the normal or open position of a jaw element allowing reception of a work nut;

FIG. 8 is a detail showing the jaw element pivoted in crimping relation to the work nut;

FIG. 8a is an elevational view of the inner face of the element in FIG. 8b: and

FIG. 8/) is a detail in side elevation of a jaw element.

DESCRIPTION OF PREFERRED EMBODIMENT Reference is directed to the accompanying drawings. and now especially to FIGS. 1-81). wherein is shown a pneumatically powered tool having a general housing 10 which includes an angle head section II detachably coupled. as by a threaded connection 12. with the front end of the housing. Supported in the housing is a conventional air driven reversible motor 13 of a radially slidable vane type. An inlet passage 14 to the tool is connectible to an external source of air having a constant pressure. A throttle valve 15 is manually operable to feed inlet air to a passage 16. A manually operable reversing valve 17 in passage 16 normally directs the air flow to one area of the motor chamber to cause forward or clockwise rotation of the motor. In an actuated through a splined driving connection 19 to a spindle 21.

The spindle extends axially into one arm 22 of the angle head. and is supported therein in bearings 23 and 24. A beveled pinion 25 on the spindle drivingly engages a bevel gear member 26 of a combined nut running and nut crimping mechanism 27 housed in the angle head. The mechanism is shown as arranged in a second arm 28 of the angle head. which arm extends at right angles to the longitudinal axis of the general housing of the tool.

The mechanism 27 has an initial first stage of operation upon application of torque to it by the spindle 21 in one direction to engage and run a work nut 29 down to a predetermined degree of tightness; and it has a subsequent second stage of operation upon receiving torque from the spindle in an opposite direction to crimp the work nut.

The bevel gear member 26 of the mechanism 27 has a stubular body which is supported in a bearing 31 and has a splined driving connection 32 with a surrounding tubular bodyof a slidable dog 34. The splined connection 32 allows axial movement of the dog relative to the gear member. The dog has a group of end jaws 35 which are drivingly engageable with complementary jaws 36 of a drive nut 37. A return spring 38 normally biases the dog axially to a position wherein the jaws of the dog are disengaged from those of the drive nut. One end of the spring abuts an overhanging shoulder of the drive nut; and its other end is seated upon a ring 39 having a bearing support upon an underlying shoulder of the dog.

A piston 41 having a tubular body sleeved upon the body of the dog is pneumatically operable in an expansible chamber 42 to slide the dog against the resistance of the spring into clutched driving engagement with the drive nut. A thrust ring bearing 43 is disposed between the piston and an overlying shoulder of the dog. A passage 44 through the angle head connects the expansible chamber with an external hose 45 leading to a side port 46 of the housing. Port 46 connects with a chamber 47. The latter also connects with passage 16 leading to the motor; and is supplied with live air from the throttle valve 15.

The drive nut 37 has a tubular body, one end of which is journaled in a bearing 48 seated in an axial recess of a cap 49 that closes the rear end of the angle head. Bearing 48 is confined to the recess by means of a retaining ring 51. The opposite end of the drive nut has bearing contact with the upper end of the gear member 26; and a thrust ring bearing 52 is provided between the annular flange of the drive nut and the overhead retaining ring 51. By means of this arrangement, the drive nut has rotation relative to the angle head and to the gear member but is curbed against relative axial movement.

The drive nut has an internal helical splined engagement with an upper screw portion of the shaft of a travel wedge 54 (FIGS. I and 5). An intermediate smooth cylindrical portion of the shaft depends slidably through the body of the gear member 26. A lower shaft portion 55 of larger diameter depends below the gear member and projects slidably through an axial opening of a gland ring 56 into the interior of a jaw holding sleeve 57. The gland ring is retained in a fixed position to the sleeve andserves as a closure to retain grease in the gear area above. Below the gland ring the shaft of the travel wedge terminates in a wedge head 58 of larger diameter than its shaft portion 55.

The Wedge head is splined to the holding sleeve for relative axial movement as well as for rotatably driving the sleeve. To permit rotation of the sleeve. the latter is loosely supported at its upper end in the angle head between an overlying shoulder of the latter and an underlying beveled surface 59 of a sleeve screw 61. The latter is entered into an open bottom end of the angle head. In this arrangement. the holding sleeve 57 has rotation relative to the angle head but is restrained against relative axial movement. A lower end of the holding sleeve projects externally of the angle head.

The holding sleeve (FIGS. 1, 4, 7) has a group of six internal longitudinally extending spline tracks 62 spaced circumferentially equally apart. In each track is slidably received a separate one of six radial splines 63 formed about the wedge head. Each spline has a downwardly and inwardly tapering flat angle surface 64 which terminates in a tip 65 common to the several splines. The axis of the tip coincides with that of the holding sleeve.

The wedge head normally has a raised position, as in FIGS. 1 and 7, under the bias of a return spring 66, in which position an annular shoulder at its top underlies the gland ring and an annular shoulder 60 of its shaft portion abuts the gear member 26. Also, in this normal position its common tip 65 is abutted slightly rearwardly of its apex by the rounded vertex ends 67 of a group of crimping levers or jaw elements 68.

There are six jaw elements. each located in a separate track 62 of the holding sleeve in underlying relation to the angle surface 64 of a separate one of the splines of the wedge head. The jaw elements are of a general right triangular form. Each has a base end 69 and an upper tail portion having inner and back walls 71, 72 terminating in the vertex 67. The base end has a rounded back corner or heel 73 pivotally seated in an inside radius or pocket 74 formed adjacent the bottom end of a related track of the holding sleeve; and the base end has a crimping toe or jaw 75 at its inner end. The jaw 75 is flat faced and in extension of the wall 71. A shallow inside radius 75a (FIGS. 81!. 8b) separates the jaw portion 75 from the upper portion of wall 71.

The several jaw elements are constantly urged by means of the load of spring 66 acting through a jaw return plunger 76 to pivot the bearing surfaces of the forwardly projecting curved portions 70 of their tail or vertex ends inwardly of the holding sleeve into abutment with the tip of the wedge head and to draw their jaw ends 75 outwardly to an open condition as in FIGS. 1 and 7. The plunger has an elongated axial stem 77 which is slidably received in an axial bore of the wedge head. The stem 77 terminates at its bottom in an inverted cup portion or head 78 of enlarged diameter which has a bearing contact with the surrounding-internal wall of the wedge head. The cup portion has a radial annular lip 79 at its bottom. in the undersurface of which is a group of six radial slots 81 (FIGS. 3, 7) spaced equally apart. In each slot is received a separate lug 82 projecting from below the mid-area of'the inner face of a jaw element. The upper wall of each slot is pressed under the load of the spring 66 upon the underlying lug 82 so as to pivot the vertex end 67 of the related jaw element inwardly into abutment with the tip' of the wedge head as in FIGS. 1 and 7. The return spring is under constant compression between opposed shoulders of the travel wedge and the plunger.

In this normal position of the jaw elements. their six inner faces 71 are in a substantially vertical position; and their jaws 75 define below the several lugs 82 a hexagonal opening for reception of a hex-form work nut 29, as appears in FIGS. 1 and 7. Accordingly. clockwise rotation of the jaw sleeve in this normal condition of the jaws will rotate and set the work nut.

It can be seen that if the wedge head 58 is caused to move axially downward relative to the holding sleeve 57. its tip and the angle surfaces 64 of its several splines will ride in a camming action over the vertexes 67 of the jaw elements causing the latter to pivot their tail ends outwardly. The outward pivoting will cause the several flat faced crimping jaws to swing inwardly in an are so as to close upon and forcefully compress or crimp corresponding flats of the work nut. as in FIG. 8. A slight inside radius 83 above the heel 73 of each jaw element is adapted in this outward pivoting action to seat over a complementary radius 84 located above the pocket 74 so as to permit the rear wall of the jaw to limit substantially upon the opposed back wall' of the related track of the holding sleeve. This arrangement serves to maintain a proper seated relation of the heel of the jaw to its pocket during pivoting of the jaw in a crimping direction.

It is to be noted in the crimping action that the jaw ends 75 of the jaw elements move relative to the corresponding flats of the work nut 29 in a radially and upwardly curved path. each defining an are which is concentric with its pivot. The flat face 75 of each jaw in penetrating a corresponding flat of the work compressively displaces a triangular volume of metal which flows inwardly to obtain a desirable locked condition of the nut and stud. When the jaws are withdrawn, a triangular indentation from which the metal was displaced appears in each flat. The deepest portion of the indentation is toward the work or lower end of the nut from where it extends angularly upward to intersect with the flat side of the nut. This manner of crimping the nut is of decided advantage in that it ensures that the jaws, as well as the tool will be readily released from the nut after the crimping cycle. It is to be noted that the flat face 75 of each jaw is defined as a summit of four beveled side walls 75 (a). (b) and (c).

Summary of the operation of the tool: The normally open jaw end of the tool, as provided by the six jaw elements 68, is first seated over the work nut, as in FIG. 1. The throttle valve 15 is then manually actuated to open condition as in FIG. 1, causing inlet air to flow to the common chamber 47. From the latter, it flows through the side port 46 and the external hose 45 to the piston chamber 42 in the angle head causing piston 41 to slide the dog 34 into driving engagement with the drive nut 37. Air also flows from chamber 47 through passage 16 to the motor. Resultant rotation of the motor is transmitted through the bevel gearing 25. 26 and dog 34' to impart clockwise rotation to the drive nut 37. The clockwise torque of the drive nut is transmitted through the helical splines to draw the travel wedge 54 upwardly so as to frictionally lock its shoulder 60 against the bevel gear 26. With this action. the bevel gear. dog. drive nut and travel wedge rotate as a unit and act through the wedge head 58 to rotate the jaw holding sleeve 57 to cause the jaw elements 68 to run down and set the work nut 29. When the work nut is driven to a predetermined degree of tightness. the resultant overload causes the motor to stall. The operator then manually shifts the reversing valve 17 causing inlet air flow to shift its direction and drive the motor in an opposite direction. C onsequent reverse rotation of the drive nut 37 relative to the travel wedge 54 causes the latter to travel linearly downward against the force of the return spring 66. In this movement. the wedge head 58 rides down the spline tracks 62 relative to the jaw holding sleeve. At this time. the coned surface of the sleeve becomes loaded against the opposed mating surface 59 of the screw 61 so that the sleeve is restrained against rotation in a loosening direction of the nut. The downwardly moving wedge head cooperates with the several jaw elements 68 to compressively and forcefully close their jaws upon and crimp the work nut. Resistance offered by the jaw elements to further pivoting as their backs stop against the wall of the sleeve stalls the motor. The operator then releases the throttle valve to closed condition. shutting off air flow to the motor. As the holding air acting in chamber 42 on the piston is then vented through the motor. spring 38 disengages the dog 34. With this action. the drive nut 37 spins freely about as the travel wedge is linearly returned to normal by the plunger spring 66. Simultaneously with this action. the several jaw elements are pivoted under the spring load of the plunger 76 to normal open condition as the wedge head restores upwardly. The angular pivoting movement of the jaws. together with the flat configuration of the jaw face 75 and the adjacent beveled sides 75a. b and c. prevent the jaws from being locked to the nut in a crimping action and allow the jaws to be easily retracted out of crimping relation with the nut. The tool is then lifted from the work and the reversing valve I7 is manually reshifted to normal condition preparatory to the next work operation.

What is claimed is:

l. A lever for crimping a side face of a nut. comprising a body of general triangular form having a base wall. front and back walls extending upwardly from the base wall and terminating in a rounded vertex end. a rounded heel connecting the lower end of the back wall with the base wall. the heel being adapted for pivotal support in a complementary pocket of a holding sleeve. a crimping toe at the lower end of the front wall adjacent the base wall adapted for effecting a crimp in a side face of a nut that might be positioned in front of the toe as a consequence of a rearward pivoting of the lever. the rounded vertex end having a portion of its curvature projecting forwardly of the front wall. the projecting curvature being adapted to present a bearing surface to a relatively moving wedge. and a lug projecting forwardly from the front wall between the ends of the latter, the lug being adapted for engagement under pressure means to effect a forward pivoting of the lever.

2. A lever as in claim 1, wherein the back wall is indented inwardly immediately above the curvature of the heel.

3. A lever as in claim 2, including a holding sleeve having a pocket in which the heel of the lever is pivotally seated. 4 I 

1. A lever for crimping a side face of a nut, comprising a body of general triangular form having a base wall, front and back walls extending upwardly from the base wall and terminating in a rounded vertex end, a rounded heel connecting the lower end of the back wall with the base wall, the heel being adapted for pivotal support in a complementary pocket of a holding sleeve, a crimping toe at the lower end of the front wall adjacent the base wall adapted for effecting a crimp in a side face of a nut that might be positioned in front of the toe as a consequence of a rearward pivoting of the lever, the rounded vertex end having a portion of its curvature projecting forwardly of the front wall, the projecting curvature being adapted to present a bearing surface to a relatively moving wedge, and a lug projecting forwardly from the front wall between the ends of the latter, the lug being adapted for engagement under pressure means to effect a forward pivoting of the lever.
 2. A lever as in claim 1, wherein the back wall is indented inwardly immediately above the curvature of the heel.
 3. A lever as in claim 2, including a holding sleeve having a pocket in which the heel of the lever is pivotally seated. 